koa-contrib-pathsegmentsstartwith

a koa middleware, call an user defined middleware if ctx.path's path segments start with a given prefix's path segments.

This is a replacement for koa-mount.

How it works

The middleware wrapper accept town params, path prefix and middleware function.

When a http request incoming, the middleware parse the given path prefix, and ctx.path, by spliting them with /. It compares the parsed array (path segments), to determine call the user defined middleware or not.

For example, user given path /api/v1/ as path prefix, and http incoming ctx.path is /api/v1/nice-cat. The middleware parse them as arrays, to compare their path segments:

1. given path /api/v1/ parsed to ['api', 'v1'] (1)
2. ctx.path /api/v1/nice-cat parsed to ['api', 'v1', 'nice-cat'] (2)
3. compare (1) & (2), because (2)'s first elements equal to (1)'s elements, so the path matched, the user defined middleware will be called.

For more information about path and path segments, please refer to RFC 2396.

See chart below for reference.

| ctx.path | prefix | matched: call middleware (Y/N) | |------------------|-----------|--------------------------------| | /api | /api | Y | | /api/ | /api | Y | | /api | /api/ | Y | | /api/ | /api/ | Y | | /api/v1 | /api/ | Y | | /api/v1 | /api/v | N | | /api/v2 | /api/v2 | Y | | /api/v2.0 | /api/v2 | N | | /api/v21 | /api/v2 | N | | /images | /image | N | | /images/flower | /image/ | Y |

Usage

This middleware is path based. If you want a simple string based one, please refer to koa-contrib-pathstringstartswith.

Install via npm or yarn.

# for npm
npm i --save koa-contrib-pathsegmentsstartwith
# for yarn
yarn add koa-contrib-pathsegmentsstartwith

Use as a Koa middleware in your app.

// import it
const pathSegmentsStartWith = require('koa-contrib-pathsegmentsstartwith')

// if ctx.path starts with `api/v1`, then call myMiddleware1
app.use(pathSegmentsStartWith('/api/v1', myMiddleware1))

// if ctx.path starts with `api/v2`, then call myMiddleware2
app.use(pathSegmentsStartWith('/api/v2', myMiddleware2))

Compare to koa-mount

• This one do not change ctx.path, this void many pains.
• This middleware do not mount Koa application.
• It's simple and easy to use.

LICENSE

The MIT License.